WO2012046947A1

WO2012046947A1 - Heat pump outdoor unit having two rows of coils of dual pipe structure and alternating type heat pump

Info

Publication number: WO2012046947A1
Application number: PCT/KR2011/004959
Authority: WO
Inventors: Chang Duk Jeon
Original assignee: Chungju National University Industrial Cooperation Foundation
Priority date: 2010-10-06
Filing date: 2011-07-07
Publication date: 2012-04-12

Abstract

The present invention relates to a heat pump outdoor unit that is capable of performing defrosting and heating at the same time, and more particularly, to a heat pump outdoor unit having two rows of coils of a dual pipe structure and an alternating type heat pump wherein each of the two rows of outdoor unit coils has a dual pipe structure and outside pipes in the dual pipe structure are selectively used as an evaporator or condenser in accordance with the outdoor conditions and the load variations, thereby improving the performance of the heat pump.

Description

HEAT PUMP OUTDOOR UNIT HAVING TWO ROWS OF COILS OF DUAL PIPE STRUCTURE AND ALTERNATING TYPE HEAT PUMP

FIG.1 shows a schematic circuit diagram showing a standard heating operation of a heat pump according to a conventional practice (which is disclosed in Korean Patent Registration No. 10-0965057 entitled `heat pump’ as filed by the same applicant as this invention, wherein the heat pump 10 includes a compressor 200, a four-way valve 210, an indoor unit 220, check valves 240, expansion valves 230, a three-way valve 250, an outdoor unit main coil 90, an outdoor unit auxiliary coil 100, an outdoor unit blower 110, and an accumulator 270, such that under the outdoor air conditions where frost is formed, the defrosting and heating operations of the heat pump can be carried out at the same time. In the state where the outdoor air has a high humidity and a temperature in a range between -2℃ and 2℃, if the outdoor unit auxiliary coil 100 is operated as a condenser so as to suppress or delay the frosting on the outdoor unit coils during the heating operation of the heat pump, the outdoor air becomes warm via the outdoor unit auxiliary coil 100 and the warm air is then passed through the outdoor unit main coil 90, such that the frosting on the outdoor unit main coil 90 can be delayed or suppressed.

However, if high temperature and high pressure refrigerant flow, which is emitted from the compressor 200 and introduced to the outdoor unit auxiliary coil 100, is low, the air passed through the outdoor unit auxiliary coil 100 cannot be sufficiently heated, thereby failing to obtain perfect defrosting effects. Contrarily, if the refrigerant flow introduced to the outdoor unit auxiliary coil 100 is high, the formation of the frost can be suppressed or delayed for a long period of time, but an amount of refrigerant flowing toward the indoor unit 220 for heating operation becomes reduced to provide poor heating capability.

So as to solve the above-mentioned problems conflicting with each other, there is a need for the development of a method and device that produces an optimal amount of refrigerant satisfying both of heating capability (COP: coefficient of performance) of a heating pump and a delay time period in the formation of frost as user`s desired levels and that accurately distributes the amount of refrigerant to the outdoor unit auxiliary coil 100 and the indoor unit 220. However, it is difficult to find such method and device from the products used in practice.

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a heat pump outdoor unit having two rows of coils of a dual pipe structure and an alternating type heat pump wherein each of the two rows of outdoor unit coils has a dual pipe structure and outside pipes in the dual pipe structure are selectively used as an evaporator or condenser in accordance with the outdoor conditions and the load variations, thereby improving the performance of the heat pump.

It is another object of the present invention to provide a heat pump outdoor unit having two rows of coils of a dual pipe structure and an alternating type heat pump that allows the outside pipes of the two rows of outdoor unit coils having the dual pipe structure to be operated as a condenser in an alternating manner under the environment where frost is formed or under the coldest weather conditions in a winter season, thereby basically preventing the frost from being formed and further improving the evaporating capability of the heat pump.

It is still another object of the present invention to provide a heat pump outdoor unit having two rows of coils of a dual pipe structure and an alternating type heat pump that allows the outside pipes of the two rows of outdoor unit coils having the dual pipe structure to be operated as an evaporator in an alternating manner during the cooling operation of the heat pump under the hottest weather conditions, thereby improving the performance of the heat pump through high condensing capability even in case where the outdoor air temperature is raised to decrease the condensing effects of the outdoor unit in the hottest weather environments.

To accomplish the above objects, according to a first aspect of the present invention, there is provided a heat pump outdoor unit adapted to perform a heat exchanging operation between outdoor air and refrigerant, the heat pump outdoor unit including: a first row of outdoor unit coil having a dual pipe structure and disposed to be first brought into contact with the outdoor air; and a second row of outdoor unit coil disposed at one side of the first row of outdoor unit coil in parallel with the first row of outdoor unit coil in such a manner as to be brought into contact with the outdoor air after the contact of the first row of outdoor unit coil with the outdoor air, wherein the first row of outdoor unit coil having the dual pipe structure has a plurality of outside pipes through which high temperature and high pressure gas refrigerant or low temperature and low pressure refrigerant is passed and a plurality of inside pipes through which low temperature and low pressure refrigerant or high temperature and high pressure gas refrigerant is passed.

To accomplish the above objects, according to a second aspect of the present invention, there is provided a heat pump outdoor unit adapted to perform a heat exchanging operation between outdoor air and refrigerant, the heat pump outdoor unit including: a first row of outdoor unit coil and a second row of outdoor unit coil each having a dual pipe structure having an independent refrigerant circuit and disposed in parallel with each other; and a plurality of outside pipes and a plurality of inside pipes of the first row of outdoor unit coil and the second row of outdoor unit coil each having the dual pipe structure disposed spaced apart from each other in parallel with each other in such a manner as to be selectively operated as a condenser or evaporator, the plurality of outside pipes having an outside introducing pipe disposed at the front end thereof so as to introduce or emit the refrigerant thereto or therefrom, an outside emitting pipe disposed at the rear end thereof so as to emit or introduce the refrigerant therefrom or thereto, and a plurality of first connecting members adapted to connect the ends of the plurality of outside pipes, and the plurality of inside pipes having a plurality of second connecting members adapted to connect the ends thereof.

To accomplish the above objects, according to a third aspect of the present invention, there is provided an alternating type heat pump including: a compressor adapted to compress refrigerant; a four-way valve adapted to allow the flow direction of high temperature and high pressure refrigerant passed through the compressor to be changed to a heating or cooling circuit; an indoor unit adapted to perform a heat exchanging operation between indoor air and the refrigerant so as to heat or cool indoor space; an outdoor unit having a first row of outdoor unit coil and a second row of outdoor unit coil each having an independent refrigerant circuit and disposed in parallel with each other, the first row of outdoor unit coil having a dual pipe structure wherein a plurality of outside pipes and a plurality of inside pipes have an independent refrigerant circuit from each other in such a manner as to be selectively operated as a condenser or evaporator; heating and cooling expansion valves adapted to reduce temperature and pressure of the flowing refrigerant; first and second three-way valves each disposed on the refrigerant lines connected to both ends of the outside pipes of the first row of outdoor unit coil so as to change the flow direction of the refrigerant passed through the outside pipes; and a controller adapted to control the first and second three-way valves such that the outside pipes of the first row of outdoor unit coil are selectively operated as a condenser or evaporator.

To accomplish the above objects, according to a fourth aspect of the present invention, there is provided an alternating type heat pump including: a compressor adapted to compress refrigerant; a four-way valve adapted to allow the flow direction of high temperature and high pressure refrigerant passed through the compressor to be changed to a heating or cooling circuit; an indoor unit adapted to perform a heat exchanging operation between indoor air and the refrigerant so as to heat or cool indoor space; an outdoor unit having a first row of outdoor unit coil and a second row of outdoor unit coil each having an independent refrigerant circuit and disposed in parallel with each other, the first row of outdoor unit coil and the second row of outdoor unit coil each having a dual pipe structure wherein a plurality of outside pipes and a plurality of inside pipes have an independent refrigerant circuit from each other in such a manner as to be selectively operated as a condenser or evaporator; heating and cooling expansion valves adapted to reduce temperature and pressure of the flowing refrigerant; first and second three-way valves disposed between the four-way valve and the front end of the outside pipes of the first row of outdoor unit coil and between the four-way valve and the front end of the outside pipes of the second row of outdoor unit coil so as to change the flow direction of the refrigerant; a third three-way valve disposed between the outside pipes of the first row of outdoor unit coil and the cooling expansion valve so as to change the flow direction of the refrigerant; and a controller adapted to control the first to third three-way valves to allow the high temperature and high pressure refrigerant to flow into at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil.

As described above, the heat pump according to the present invention has the following effects in accordance with the operating methods of the dual pipe structure of the outdoor unit.

First, when the heat pump is operated in a cooling mode in a summer season, the outside pipes and the inside pipes of the outdoor unit are all operated as a condenser, and when the heat pump is operated in a heating mode in a winter season, the outside pipes and the inside pipes of the outdoor unit are all operated as an evaporator, thereby performing the same operations as general heat pumps.

Second, if an outdoor air temperature is raised at the time of the cooling operation to decrease the condensing capability of the outdoor unit, the outside pipes of the first row of outdoor unit coil are operated as an evaporator, thereby enhancing the cooling performance of the heat pump through the improvement of the condensing capability.

Third, if an outdoor air temperature is lowered at the time of the heating operation to decrease the evaporating capability of the outdoor unit, the outside pipes of the outdoor unit are operated as a condenser, thereby enhancing the heating performance of the heat pump through the improvement of the evaporating capability.

Fourth, under the outdoor air conditions where frost is easily formed, the formation of the frost on the outdoor unit can be perfectly prevented and the frost already formed thereon can be completely removed.

FIG.1 is a schematic circuit diagram showing a refrigerant flow in a heat pump according to a conventional practice.

FIG.2 is a perspective view showing a heat pump outdoor unit according to a first embodiment of the present invention.

FIG.3 is a sectional view showing a portion of a first row of outdoor unit coil in the heat pump outdoor unit according to the first embodiment of the present invention.

FIG.4 is a sectional view showing a portion of a second row of outdoor unit coil in the heat pump outdoor unit according to the first embodiment of the present invention.

FIG.5 is an exploded perspective view showing the first and second rows of outdoor unit coils according to the first embodiment of the present invention.

FIG.6 is a schematic circuit diagram showing a refrigerant flow in an alternating type heat pump according to the first embodiment of the present invention, wherein a standard heating operation is performed.

FIG.7 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first row of outdoor unit coil.

FIG.8 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein a standard cooling operation is performed.

FIG.9 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein the outside pipes of the first row of outdoor unit coil are operated as an evaporator when a cooling operation is performed under the hottest weather conditions.

FIG.10 is a schematic circuit diagram showing a refrigerant flow in an alternating type heat pump according to a second embodiment of the present invention, wherein a standard heating operation is performed.

FIG.11 is perspective and sectional views showing a portion of an outdoor unit having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the outdoor unit is shown when a standard heating operation is performed.

FIG.12 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first row of outdoor unit coil.

FIG.13 is perspective and sectional views showing a portion of a first row of outdoor unit coil having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the first row of outdoor unit coil is shown when defrosting and heating operations are performed.

FIG.14 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the second row of outdoor unit coil.

FIG.15 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first and second rows of outdoor unit coils.

FIG.16 is a schematic circuit diagram showing the refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein a standard cooling operation is performed.

FIG.17 is perspective and sectional views showing a portion of an outdoor unit having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the outdoor unit is shown when a standard cooling operation is performed.

FIG.18 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein the outside pipes of the first row of outdoor unit coil are operated as an evaporator when a cooling operation is performed under the hottest weather conditions.

FIG.19 is perspective and sectional views showing a portion of the first row of outdoor unit coil having the dual pipe structure according to the second embodiment of the present invention, wherein a cooling operation is performed under the hottest weather conditions.

Hereinafter, an explanation on the configuration and operation of a heat pump outdoor unit according to preferred embodiments of the present invention will be in detail given with reference to the attached drawings. First, FIG.2 is a perspective view showing a heat pump outdoor unit 250 according to a first embodiment of the present invention. The outdoor unit 250 largely includes a first row of outdoor unit coil 250-1 adapted to be first brought into contact with outdoor air and a second row of outdoor unit coil 250-2 disposed at one side of the first row of outdoor unit coil in parallel with the first row of outdoor unit coil 250-1 and adapted to be brought into contact with the outdoor air after the contact of the first row of outdoor unit coil 250-1 with the outdoor air. According to a first embodiment of the present invention, the first row of outdoor unit coil 250-1 has a dual pipe structure.

FIG.3 is a sectional view showing a portion of the first row of outdoor unit coil in the heat pump outdoor unit according to a first embodiment of the present invention. The first row of outdoor unit coil 250-1 includes a plurality of fins 260-1 disposed to expand a heat transfer area, a plurality of outside pipes 260-4 adapted to be operated as a condenser at the time of performing an operation under frosting and cold weather conditions, a plurality of inside pipes 260-5 adapted to be always operated as an evaporator at the time of a heating operation, a plurality of U-shaped bands 260-7 each adapted to connect the inside pipes 260-5 to each other, and a plurality of H-shaped connectors 260-6 each adapted to connect the outside pipes 260-4 to each other. Upon the operation under the frosting and cold weather conditions, high temperature and high pressure gas refrigerant flows along the outside pipes 260-4 and low temperature and low pressure refrigerant flows along the inside pipes 260-5.

FIG.4 is a sectional view showing a portion of the second row of outdoor unit coil in the heat pump outdoor unit according to the first embodiment of the present invention. The second row of outdoor unit coil 250-2 includes a plurality of fins 260-1 disposed to expand a heat transfer area, a plurality of outside pipes 260-4 adapted to be operated as an evaporator at the time of a standard heating operation and an operation of frosting and cold weather conditions and operated as a condenser at the time of a standard cooling operation and an operation of hot weather conditions, and a plurality of U-shaped bands 260-7 each adapted to connect the outside pipes 260-4 to each other.

FIG.5 is an exploded perspective view showing the first and second rows of outdoor unit coils according to the first embodiment of the present invention. The whole configuration and the connection structure of the outdoor unit will be described with reference to FIG.5. First, a detailed structure of the outside pipes and the inside pipes of the first row of outdoor unit coil 250-1 will be briefly described. The outside pipes 260-4 include a pair of outside introducing and emitting pipes 260-2 and 260-3 through which refrigerant is introduced and emitted, a plurality of intermediate outside pipes connecting the pair of outside introducing and emitting pipes 260-2 and 260-3 to each other, and a plurality of first connecting members connecting the pair of outside introducing and emitting pipes 260-2 and 260-3 and the intermediate outside pipes or the two intermediate outside pipes disposed in parallel with each other. In this case, the first connecting members are the H-shaped connectors 260-6 as shown in FIG.3.

The inside pipes 260-5 include a pair of inside introducing and emitting pipes through which refrigerant is introduced and emitted, a plurality of intermediate inside pipes connecting the pair of inside introducing and emitting pipes to each other, and a plurality of second connecting members connecting the pair of inside introducing and emitting pipes and the intermediate inside pipes or the two intermediate inside pipes disposed in parallel with each other. In this case, the second connecting members are the U-shaped bands 260-7 as shown in FIG.3. Now, an explanation on the whole configuration and the connection structure of the outdoor unit will be given with reference to FIG.5. As shown in FIG.5, the high temperature and high pressure gas refrigerant emitted from a compressor at the time of the operation of frosting and cold weather conditions is introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1 through an inlet of the outside pipes 260-4. Since the outside pipes 260-4 are connected through the H-shaped connectors 260-6, the refrigerant flows along the outside pipes 260-4, and while the heat of the refrigerant is being decreased by means of the inside pipes 260-5 operated as an evaporator and outdoor air, the refrigerant is condensed and becomes liquid refrigerant. After that, the liquid refrigerant is discharged from the first row of outdoor unit coil 250-1. On the other hand, low temperature and low pressure refrigerant passed through an expansion valve is introduced to the inside pipes 260-5 of the first row of outdoor unit coil 250-1 through an inlet of the inside pipes 260-5. Since the inside pipes 260-5 are connected through the U-shaped bands 260-7, the refrigerant flows along the inside pipes 260-5, and while the refrigerant is receiving the heat from the high temperature refrigerant flowing along the outside pipes 260-4, the refrigerant is evaporated.

The low temperature and low pressure gas and liquid refrigerant, which is emitted from the outlet of the inside pipes 260-5 of the first row of outdoor unit coil 250-1, is introduced to the inlet of the second row of outdoor unit coil 250-2, and while flowing along the second row of outdoor unit coil 250-2, the refrigerant receives the heat from the air whose temperature is raised while being passed through the first row of outdoor unit coil 250-1. Thus, the evaporation is finished and the refrigerant becomes perfect gas refrigerant. After that, the gas refrigerant is emitted from the second row of outdoor unit coil 250-2. As appreciated from the above processes, unlike general heat pump outdoor units, since the inside pipes 260-5 serving as an evaporator are not brought into direct contact with the cold air having humidity, no frosting occurs even under the frosting conditions. Further, even under the cold weather conditions like 20 C below zero, the inside pipes 260-5 receive the heat from the outside pipes 260-4 and performs stable evaporation, thereby ensuring good performance of the heat pump at a low temperature.

Moreover, if the refrigerant is evaporated from the liquid phase to the gas phase in the outdoor unit serving as an evaporator, the specific volume is increased, and when the refrigerant flows along the passages having the same sectional areas, the frictional loss becomes increased toward the rear portion of the outdoor unit. According to the present invention, however, as shown in FIG.5, the refrigerant has a first evaporation step along the inside pipes 260-5 of the first row of outdoor unit coil 250-1 and has a second evaporation step along the second row of outdoor unit coil 250-2 having the outside pipes having a larger size than the inside pipes 260-5 of the first row of outdoor unit coil 250-1, thereby compensating for the frictional loss caused by the increase of the specific volume of the refrigerant and improving the performance of the outdoor unit.

Hereinafter, an explanation on the configuration, operation and operating method of an alternating type heat pump according to the first embodiment of the present invention will be in detail given with reference to the attached drawings. FIG.6 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein a standard heating operation is performed. As shown in FIG.6, high temperature and high pressure gas refrigerant emitted from a compressor 200 is condensed in an indoor unit 220 via a four-way valve 210, a first pipe 330-1 and a second pipe 330-2, and thus, indoor space is heated with the condensed heat. The condensed refrigerant is passed through a heating expansion valve 230-1 and a check valve 240-2, such that a portion of the refrigerant is sent to the outside pipes of the first row of outdoor unit coil 250-1 and is evaporated by receiving heat from outdoor air and the rest is sent to the inside pipes of the first row of outdoor unit coil 250-1 and is evaporated by receiving heat from the outside pipes of the first row of outdoor unit coil 250-1. While flowing along the second row of outdoor unit coil 250-2 connected side by side with the first row of outdoor unit coil 250-1, the evaporated refrigerant in the inside pipes of the first row of outdoor unit coil 250-1 receives the heat from the outdoor air whose temperature is raised while being passed through the first row of outdoor unit coil 250-1 and is completely evaporated. At this time, a first three-way valve 300-1 communicates with the rear end of a cooling expansion valve 230-2, and a second three-way valve 300-2 is controlled to be blocked from a third pipe 330-3. The evaporated refrigerant is added at the rear end of the outdoor unit and is absorbed to the compressor 200 via a fourth pipe 330-4, the four-way valve 210 and an accumulator 280, thereby completing a heating cycle.

FIG.7 is a schematic circuit diagram showing the refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first row of outdoor unit coil. As shown in FIG.7, high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the four-way valve 210, such that a portion of the refrigerant is introduced to the outside pipes of the first row of outdoor unit coil 250-1 via the third pipe 330-3 and the second three-way valve 300-2 and is condensed therein, and the rest is condensed in the indoor unit 220 via the second pipe 330-2 and heats the indoor space with the condensed heat. The refrigerant condensed in the outside pipes of the first row of outdoor unit coil 250-1 is added to the refrigerant condensed while being passed through the indoor unit 220 at the front end of the heating expansion valve 230-1 via the first three-way valve 300-1. While the added refrigerant is flowing along the inside pipes of the first row of outdoor unit coil 250-1 via the heating expansion valve 230-1 and the check valve 240-2, the refrigerant receives the heat from the outside pipes along which high temperature refrigerant flows and is thus evaporated. Next, while the refrigerant emitted from the first row of outdoor unit coil 250-1 is being passed through the second row of outdoor unit coil 250-2, the refrigerant receives the heat from the outdoor air and is completely evaporated.

The evaporated refrigerant is absorbed to the compressor 200 via the fourth pipe 330-4, the four-way valve 210 and the accumulator 280, thereby completing a defrosting and low temperature heating cycle. Therefore, the inside pipes of the first row of outdoor unit coil 250-1 perform their evaporation process, while being not contacted with the outdoor air containing humidity, and the second row of outdoor unit coil 250-2 performs the evaporation process, while being contacted with the air whose temperature is raised while being passed through the first row of outdoor unit coil 250-1, thereby basically preventing frost from being formed and substantially improving the performance of the heat pump even under the frosting conditions.

FIG.8 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein a standard cooling operation is performed. As shown in FIG.8, high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the four-way valve 210 and the fourth pipe 330-4, such that a portion of the refrigerant is introduced to the outside pipes of the first row of outdoor unit coil 250-1 via the second three-way valve 300-2 and is condensed therein, and the rest is condensed by means of outdoor air, while being passed through the second row of outdoor unit coil 250-2 and the inside pipes of the first row of outdoor unit coil 250-1. The refrigerant condensed in the outside pipes of the first row of outdoor unit coil 250-1 is added to the refrigerant condensed in the inside pipes of the first row of outdoor unit coil 250-1 at the front end of the cooling expansion valve 230-2 via the first three-way valve 300-1. While the added refrigerant is evaporated in the indoor unit 220 via the cooling expansion valve 230-2 and a check valve 240-1, the refrigerant receives the heat from the outdoor air and cools the indoor space. The evaporated refrigerant is absorbed to the compressor 200 via the second pipe 330-2, the four-way valve 210 and the accumulator 280, thereby completing a cooling cycle.

FIG.9 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the first embodiment of the present invention, wherein the outside pipes of the first row of outdoor unit coil are operated as an evaporator at the time of a cooling operation under the hottest weather conditions. As shown in FIG.9, high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the four-way valve 210 and the fourth pipe 330-4 and is condensed via the second row of outdoor unit coil 250-2 and the first row of outdoor unit coil 250-1 sequentially. The condensed refrigerant is passed through the cooling expansion valve 230-2 and the check valve 240-1, such that a portion of the refrigerant is introduced to the outside pipes of the first row of outdoor unit coil 250-1 via the first three-way valve 300-1, and the rest is sent to the indoor unit 220, thereby being evaporated to cool the indoor space.

The low temperature refrigerant sent to the outside pipes of the first row of outdoor unit coil 250-1 receives the heat from the inside pipes of the first row of outdoor unit coil 250-1 in which condensing process is performed, thereby allowing the condensing process in the inside pipes to be gently performed. The condensing process is effectively performed even under the hottest weather conditions having the outdoor air temperature of more than 35 C. Further, the outdoor air whose temperature is dropped, while being passed through the first row of outdoor unit coil 250-1, assists in the condensing process of the refrigerant in the second row of outdoor unit coil 250-2. The refrigerant evaporated in the outside pipes of the first row of outdoor unit coil 250-1 is added to the refrigerant passed through the second three-way valve 300-2 and the third pipe 330-3 and then the indoor unit 220 and the second pipe 330-2. The added refrigerant is absorbed to the compressor 200 via the four-way valve 210 and the accumulator 280, thereby completing a cooling cycle. Moreover, if the refrigerant is condensed from the gas phase to the liquid phase in the outdoor unit serving as a condenser, the specific volume is decreased, and when the refrigerant flows along the passages having the same sectional areas, the acceleration force becomes decreased toward the rear portion of the outdoor unit. According to the present invention, however, the refrigerant has a first condensing step along the outside pipes of the second row of outdoor unit coil 250-2 and has a second condensing step in the inside pipes of the first row of outdoor unit coil 250-1 having a smaller size than the outside pipes of the second row of outdoor unit coil 250-2, thereby compensating for the reduction of the acceleration force caused by the decrease of the specific volume of the refrigerant and improving the performance of the outdoor unit.

Now, an explanation on the configuration, operation and operating method of an alternating type heat pump having an outdoor unit having a dual pipe structure according to a second embodiment of the present invention will be in detail given with reference to the attached drawings. The second embodiment of the present invention is different from the first embodiment of the present invention in that first to third three-way valves 300-1 to 300-3, first to four check valves 240-1 to 240-4, an inside heat exchanger 290, a hot gas bypass valve 270 are provided. Unlike the first embodiment of the present invention, the second embodiment of the present invention has first and second rows of outdoor unit coils 250-1 and 250-2 each having a dual pipe structure.

FIG.10 is a schematic circuit diagram showing the refrigerant flow in an alternating type heat pump according to the second embodiment of the present invention, wherein a standard heating operation is performed. As shown in FIG.10, high temperature and high pressure gas refrigerant emitted from a compressor 200 is all condensed in an indoor unit 220 via a four-way valve 210, a first pipe 330-1 and a second pipe 330-2, thereby heating the indoor space with the condensed heat. At this time, so as to prevent the high temperature and high pressure gas refrigerant emitted from the compressor 200 from being introduced to the front ends of the first and second rows of outdoor unit coils 250-1 and 250-2, the hot gas bypass valve 270 and the first to third three-way valves 300-1 to 300-3 are controlled by means of a controller.

The refrigerant condensed by means of the indoor unit 220 is sent to an outdoor unit 250 via the inside heat exchanger 290, a heating expansion valve 230-2 and the first check valve 240-1. At this time, the refrigerant is evaporated while being passed through the inside pipes 260-5 and the outside pipes 260-4 of the first and second rows of outdoor unit coils 250-1 and 250-2, and the evaporated refrigerant is heat-exchanged with high temperature refrigerant passed through the indoor unit 220 by means of the inside heat exchanger 290, thereby improving the degree of superheat. After that, the refrigerant is absorbed to the compressor 200 via the fourth check valve 240-4, the four-way valve 210 and the accumulator 280, sequentially, thereby completing a heating cycle. That is, in the operation as shown in FIG.10, the first and second rows of outdoor unit coils 250-1 and 250-2 are all operated as an evaporator.

FIG.11 is perspective and sectional views showing a portion (excepting the U-shaped bands 260-7) of the first or second row of outdoor unit coil having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the outdoor unit is shown when a standard heating operation is performed. As shown in the left portion of FIG.11, low temperature and low pressure refrigerant emitted from the expansion valve (which is not shown in FIG.11) is passed through the outside pipes 260-4 and the inside pipes 260-5 of the first and second rows of outdoor unit coils 250-1 and 250-2 and receives the heat from the outdoor air, thereby being operated as an evaporator in which the refrigerant is evaporated.

FIG.12 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first row of outdoor unit coil 250-1. As shown in FIG.12, a portion of the high temperature and high pressure gas refrigerant emitted from the compressor 200 is adjusted in quantity by means of the hot gas bypass valve 270 and is introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1 via the hot gas bypass valve 270 and the first three-way valve 300-1. At this time, the first three-way valve 300-1 is opened by means of the controller to allow the high temperature and high pressure gas refrigerant to be introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1, and the second three-way valve 300-2 is closed by means of the controller to prevent the high temperature and high pressure gas refrigerant from being introduced to the outside pipes 260-4 of the second row of outdoor unit coil 250-2. Also, the hot gas bypass valve 270 is controlled by means of the controller to adjust the flow of the high temperature and high pressure gas refrigerant being introduced to the front end of the outside pipes 260-4 of the first row of outdoor unit coil 250-1.

The high temperature and high pressure gas refrigerant being introduced to the front end of the outside pipes 260-4 of the first row of outdoor unit coil 250-1 sends the condensed heat to the frost formed on the first row of outdoor unit coil 250-1 and removes the frost therefrom. That is, the outside pipes 260-4 of the first row of outdoor unit coil 250-1 are operated as a condenser, and the condensed refrigerant is added to the refrigerant passed through the heating expansion valve 230-2 and the first check valve 230-1 at the inlet of the rear end of the inside pipes 260-5 of the first row of outdoor unit coil 250-1.

On the other hand, the rest of the refrigerant emitted from the compressor 200, excepting the refrigerant passed through the hot gas bypass valve 270, is condensed in the indoor unit 220 and heats the indoor space with the condensed heat. The condensed refrigerant is passed through the inside heat exchanger 290, the heating expansion valve 230-2 and the first check valve 240-1 and is then added to the refrigerant passed through the outside pipes 260-4 of the first row of outdoor unit coil 250-1 and emitted from the rear end thereof. The added refrigerant is introduced to the outdoor unit 250. That is, the added refrigerant is introduced to the inside pipes 260-5 of the first row of outdoor unit coil 250-1 and the inside pipes 260-5 and the outside pipes 260-4 of the second row of outdoor unit coil 250-2.

The refrigerant evaporated while being passed through the outdoor unit 250 is passed through the fourth pipe 330-4 and is then heat-exchanged with high temperature refrigerant passed through the indoor unit 220 by means of the inside heat exchanger 290, thereby improving the degree of superheat. After that, the refrigerant is absorbed to the compressor 200 via the fourth check valve 240-4, the four-way valve 210 and the accumulator 280, sequentially, thereby completing a partial defrosting and heating cycle.

FIG.13 is perspective and sectional views showing a portion (excepting the U-shaped bands 260-7) of the first row of outdoor unit coil having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the first row of outdoor unit coil 250-1 is shown when defrosting and heating operations are performed. As shown in FIG.13, high temperature and high pressure gas refrigerant which is passed through the hot gas bypass valve 270 and the first three-way valve 300-1 is introduced to an outside introducing pipe 260-2 of the first row of outdoor unit coil 250-1.

The high temperature and high pressure gas refrigerant flows along the outside pipes 260-4 of the first row of outdoor unit coil 250-1 and is condensed therein. The condensed heat generated upon the condensation is sent partially to the frost formed on the first row of outdoor unit coil 250-1 so as to remove the frost therefrom and is sent partially to the inside pipes 260-5 of the first row of outdoor unit coil 250-1 so as to assist the evaporation of the refrigerant passed through the inside pipes 260-5 of the first row of outdoor unit coil 250-1. The refrigerant condensed while being passed through the outside pipes 260-4 of the first row of outdoor unit coil 250-1 is emitted from the outside emitting pipe 260-3 and is then added to the refrigerant passed through the expansion valve (which is not shown in FIG.13) at the inlet of the rear end of the outdoor unit 250. The added refrigerant is introduced to the inside pipes 260-5 of the first row of outdoor unit coil 250-1 and to the second row of outdoor unit coil 250-2 and is then evaporated thereinto. The evaporated refrigerant is sent to the inside heat exchanger 290.

FIG.14 is a schematic circuit diagram showing a refrigerant flow of the second row of outdoor unit coil according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the second row of outdoor unit coil 250-2. As shown in FIG.14, a portion of the high temperature and high pressure gas refrigerant emitted from the compressor 200 is adjusted in quantity by means of the hot gas bypass valve 270 and is introduced to the outside pipes 260-4 of the second row of outdoor unit coil 250-2 via the hot gas bypass valve 270 and the second three-way valve 300-2. At this time, the first three-way valve 300-1 is closed by means of the controller to prevent the high temperature and high pressure gas refrigerant from being introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1, and the second three-way valve 300-2 is opened by means of the controller to allow the high temperature and high pressure gas refrigerant to be introduced to the outside pipes 260-4 of the second row of outdoor unit coil 250-2.

The high temperature and high pressure gas refrigerant being introduced to the front end of the outside pipes 260-4 of the second row of outdoor unit coil 250-2 is condensed therein, and the condensed heat is sent to the frost formed on the second row of outdoor unit coil 250-2 and removes the frost therefrom. That is, the outside pipes 260-4 of the second row of outdoor unit coil 250-2 are operated as a condenser, and the condensed refrigerant is added to the refrigerant passed through the heating expansion valve 230-2 and the first check valve 230-1 at the inlet of the rear end of the outside pipes 260-4 of the second row of outdoor unit coil 250-2.

On the other hand, the rest of the refrigerant emitted from the compressor 200, excepting the refrigerant passed through the hot gas bypass valve 270, is introduced to the indoor unit 220 and condensed therein to heat the indoor space with the condensed heat. The condensed refrigerant through the indoor unit 220 is passed through the inside heat exchanger 290, the heating expansion valve 230-2 and the first check valve 240-1, sequentially and is then introduced to the outside pipes 260-4 and the inside pipes 260-5 of the first row of outdoor unit coil 250-1. Next, the refrigerant is added to the refrigerant passed through the outside pipes 260-4 of the second row of outdoor unit coil 250-2 and is then introduced to the inside pipes 260-5 of the second row of outdoor unit coil 250-2.

The refrigerant evaporated while being passed through the outside pipes 260-4 and the inside pipes 260-5 of the first row of outdoor unit coil 250-1 and the inside pipes 260-5 of the second row of outdoor unit coil 250-2 is passed through the fourth pipe 330-4 and is then heat-exchanged with high temperature refrigerant passed through the indoor unit 220 by means of the inside heat exchanger 290, thereby improving the degree of superheat. After that, the refrigerant is absorbed to the compressor 200 via the fourth check valve 240-4, the four-way valve 210 and the accumulator 280, sequentially, thereby completing a partial defrosting and heating cycle.

FIG.15 is a schematic circuit diagram showing a refrigerant flow of the first and second rows of outdoor unit coils according to the second embodiment of the present invention, wherein defrosting and heating are performed at the same time on the first and second rows of outdoor unit coils. As shown in FIG.15, a portion of the high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the hot gas bypass valve 270, such that the refrigerant is introduced partially to the outside pipes 260-4 of the first row of outdoor unit coil 250-1 via the first three-way valve 300-1 and the refrigerant is introduced partially to the outside pipes 260-4 of the second row of outdoor unit coil 250-2 via the second three-way valve 300-2. At this time, the first and second three-way valves 300-1 and 300-2 are opened by means of the controller to allow the outside pipes 260-4 of the first row of outdoor unit coil 250-1 and the outside pipes 260-4 of the second row of outdoor unit coil 250-2 to be all operated as a condenser. Further, the hot gas bypass valve 270 is controlled by means of the controller to adjust the flow of the high temperature and high pressure gas refrigerant being introduced to the front end of the outside pipes 260-4 of the outdoor unit 250.

The high temperature and high pressure gas refrigerant being introduced to the outside pipes 260-4 of the first and second rows of outdoor unit coils 250-1 and 250-2 is condensed therein to generate condensed heat, such that a portion of the condensed heat is used to remove the frost formed on the first and second rows of outdoor unit coils 250-1 and 250-2 and the rest is sent to the inside pipes 260-5 to assist the evaporation of the refrigerant passed through the inside pipes 260-5. Next, the condensed refrigerant is added to the refrigerant passed through the heating expansion valve 230-2 at the inlet of the rear end of the outdoor unit 250.

On the other hand, the rest of the refrigerant emitted from the compressor 200, excepting the refrigerant passed through the hot gas bypass valve 270, is condensed in the indoor unit 220 to heat the indoor space with the condensed heat. The condensed refrigerant through the indoor unit 220 is passed through the inside heat exchanger 290, the heating expansion valve 230-2 and the first check valve 240-1, sequentially and is then added to the refrigerant passed through the outside pipes 260-4 of the outdoor unit 250. After that, the added refrigerant is introduced to the inside pipes 260-5 of the outdoor unit 250. Next, the refrigerant evaporated while being passed through the inside pipes 260-5 of the outdoor unit 250 is heat-exchanged with high temperature refrigerant passed through the indoor unit 220 by means of the inside heat exchanger 290, thereby improving the degree of superheat. After that, the refrigerant is absorbed to the compressor 200 via the fourth check valve 240-4, the four-way valve 210 and the accumulator 280, sequentially, thereby completing a whole defrosting and heating cycle.

FIG.16 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein a standard cooling operation is performed. As shown in FIG.16, high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the four-way valve 210 and the third check valve 240-3 and is then introduced to the outside pipes 260-4 and the inside pipes 260-5 of the first and second rows of outdoor unit coils 250-1 and 250-2. Next, the refrigerant is heat-exchanged with outdoor air and is thus condensed therein. At this time, the first and second three-way valves 300-1 and 300-2 are opened in a forward direction by means of the controller to allow the refrigerant to be introduced to the front end of the outside pipes 260-4 of the first and second rows of outdoor unit coils 250-1 and 250-2 and to be emitted from the rear end thereof. Therefore, the outside pipes 260-4 and the inside pipes 260-5 of the first and second rows of outdoor unit coils 250-1 and 250-2 are all operated as a condenser. The condensed refrigerant is evaporated in the indoor unit 220 via the cooling expansion valve 230-1, the second check valve 240-2 and the inside heat exchanger 290 to receive heat from the outdoor air, thereby cooling the indoor space. The evaporated refrigerant is absorbed to the compressor 200 via the four-way valve 210 and the accumulator 280, thereby completing a cooling cycle.

FIG.17 is perspective and sectional views showing a portion (excepting the U-shaped bands) of an outdoor unit having a dual pipe structure according to the second embodiment of the present invention, wherein a refrigerant flow of the first row of outdoor unit coil 250-1 or the second row of outdoor unit coil 250-2 is shown when a standard cooling operation is performed. At this time, the refrigerant flow of the first row of outdoor unit coil 250-1 is the same as of the second row of outdoor unit coil 250-2. As shown in the left portion of FIG.17, the high temperature and high pressure refrigerant emitted from the compressor (which is not shown in FIG.17) is introduced to the outside pipes 260-4 and the inside pipes 260-5 of the first and second rows of outdoor unit coils 250-1 and 250-2 and emits the heat to the outdoor air, thereby being operated as a condenser in which the refrigerant is condensed.

FIG.18 is a schematic circuit diagram showing a refrigerant flow in the alternating type heat pump according to the second embodiment of the present invention, wherein the outside pipes 260-4 of the first row of outdoor unit coil 250-1 are operated as an evaporator at the time of a cooling operation under the hottest weather conditions. For example, Under the hottest weather conditions having the outdoor air temperature of more than 35 C, the refrigerant temperature in the first and second rows of outdoor unit coils 250-1 and 250-2 operated as a condenser does not have a big difference from the outdoor air temperature, such that the condensing operation is not performed well to reduce the condensing capability, thereby making the cooling efficiency of the system badly deteriorated.

Therefore, as shown in FIG.18, high temperature and high pressure gas refrigerant emitted from the compressor 200 is passed through the four-way valve 210 and the third check valve 240-3, such that a portion of the refrigerant is introduced to the inside pipes 260-5 of the first row of outdoor unit coil 250-1 and the rest is introduced to the outside pipes 260-4 and the inside pipes 260-5 of the second row of outdoor unit coil 250-2. That is, the refrigerant is not introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1.

At this time, the second three-way valve 300-2 is opened by means of the controller to allow the high temperature and high pressure gas refrigerant emitted from the compressor 200 to be introduced to the outside pipes 260-4 of the second row of outdoor unit coil 250-2, the first three-way valve 300-1 is closed by means of the controller to prevent the high temperature and high pressure gas refrigerant from being introduced to the front end of the outside pipes 260-4 of the first row of outdoor unit coil 250-1, and the first and third three-way valves 300-1 and 300-3 are controlled by means of the controller to allow low temperature and low pressure refrigerant passed through the second check valve 240-2 to be introduced partially to the rear end of the outside pipes 260-4 of the first row of outdoor unit coil 250-2 and to be emitted to the front end thereof.

The refrigerant flowing along the outside pipes 260-4 and the inside pipes 260-5 of the second row of outdoor unit coil 250-2 sends the heat to the outdoor air and is thus condensed, and the refrigerant flowing along the inside pipes 260-5 of the first row of outdoor unit coil 250-1 sends the heat to the low temperature refrigerant flowing along the outside pipes 260-4 of the first row of outdoor unit coil 250-1 and is thus condensed. The condensed refrigerant is passed through the cooling expansion valve 230-1 and becomes low temperature and low pressure refrigerant. The low temperature and low pressure refrigerant is passed through the second check valve 240-2, such that a portion of the refrigerant is introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1 via the third three-way valve 300-3 to assist the condensing operation of the refrigerant in the inside pipes 260-5 of the first row of outdoor unit coil 250-1, and the rest is evaporated in the indoor unit 220 via the inside heat exchanger 290 and absorbs the heat from the outdoor air to cool the inside space.

The refrigerant evaporated in the indoor unit 220 is added to the refrigerant evaporated in the outside pipes 260-4 of the first row of outdoor unit coil 250-1 at the front end of the four-way valve 210 and is then absorbed to the compressor 200 via the four-way valve 210 and the accumulator 280, sequentially, thereby completing a cooling cycle under the hottest weather conditions.

FIG.19 is perspective and sectional views showing a portion (excepting the U-shaped bands 260-7) of the first row of outdoor unit coil 250-1 having the dual pipe structure according to the second embodiment of the present invention, wherein a cooling operation is performed under the hottest weather conditions. As shown in FIG.19, the high temperature and high pressure refrigerant emitted from the compressor (which is not shown in FIG.19) is introduced to the front end of the inside pipes 260-5 of the first row of outdoor unit coil 250-1, and low temperature and low pressure refrigerant emitted from the expansion valve (which is not shown in FIG.19) is introduced to the outside pipes 260-4 of the first row of outdoor unit coil 250-1 via the outside introducing pipe 260-3 thereof.

The low temperature and low pressure refrigerant flowing along the outside pipes 260-4 receives the heat from the high temperature and high pressure refrigerant flowing along the inside pipes 260-5 and is thus evaporated, and the refrigerant in the inside pipes 260-5 loses the heat and is thus condensed. The refrigerant evaporated in the outside pipes 260-4 flows toward the compressor through the outside emitting pipe 260-2, and the refrigerant condensed in the inside pipes 260-5 flows toward the expansion valve. Under the hottest weather conditions, during this process, the condensing operation of the refrigerant flowing along the inside pipes 260-5 of the first row of outdoor unit coil 250-1 is accelerated, and further, the air introduced to the first row of outdoor unit coil 250-1 is sent at the cooled state to the second row of outdoor unit coil 250-2 to accelerate the condensing operation of the refrigerant in the second row of outdoor unit coil 250-2, thereby improving the total condensing capability of the outdoor unit.

As described above, the alternating type heat pump according to the present invention is provided with the plurality of three-way valves adapted to change the refrigerant circuits, such that the outside pipes of the outdoor unit are selectively operated as a condenser or evaporator in accordance with the load conditions and the temperature and humidity of the outdoor air in the heat pump, thereby improving the performance of the heat pump. Especially, the alternating type heat pump according to the present invention is capable of perfectly removing the frost formed on the outdoor unit and preventing the frost from being formed thereon, under the outdoor air conditions where the frost is formed during the heating operation in a winter season, while heating the indoor space.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

Claims

A heat pump outdoor unit adapted to perform a heat exchanging operation between outdoor air and refrigerant, the heat pump outdoor unit comprising:

a first row of outdoor unit coil having a dual pipe structure and disposed to be first brought into contact with the outdoor air; and

a second row of outdoor unit coil disposed at one side of the first row of outdoor unit coil in parallel with the first row of outdoor unit coil in such a manner as to be brought into contact with the outdoor air after the contact of the first row of outdoor unit coil with the outdoor air,

wherein the first row of outdoor unit coil having the dual pipe structure has a plurality of outside pipes through which high temperature and high pressure gas refrigerant or low temperature and low pressure refrigerant is passed and a plurality of inside pipes through which low temperature and low pressure refrigerant or high temperature and high pressure gas refrigerant is passed.
The heat pump outdoor unit according to claim 1, wherein the plurality of outside pipes and the plurality of inside pipes are spaced apart from each other in parallel with each other, the plurality of outside pipes having an outside introducing pipe disposed at the front end thereof so as to introduce or emit the refrigerant thereto or therefrom, an outside emitting pipe disposed at the rear end thereof so as to emit or introduce the refrigerant therefrom or thereto, and a plurality of first connecting members adapted to connect the ends of the plurality of outside pipes, and the plurality of inside pipes having a plurality of second connecting members adapted to connect the ends thereof.
The heat pump outdoor unit according to claim 1, wherein each of the first connecting members is an H-shaped connector, and each of the second connecting members is a U-shaped band.
A heat pump outdoor unit adapted to perform a heat exchanging operation between outdoor air and refrigerant, the heat pump outdoor unit comprising:

a first row of outdoor unit coil and a second row of outdoor unit coil each having a dual pipe structure having an independent refrigerant circuit and disposed in parallel with each other; and

a plurality of outside pipes and a plurality of inside pipes of the first row of outdoor unit coil and the second row of outdoor unit coil each having the dual pipe structure disposed spaced apart from each other in parallel with each other in such a manner as to be selectively operated as a condenser or evaporator, the plurality of outside pipes having an outside introducing pipe disposed at the front end thereof so as to introduce or emit the refrigerant thereto or therefrom, an outside emitting pipe disposed at the rear end thereof so as to emit or introduce the refrigerant therefrom or thereto, and a plurality of first connecting members adapted to connect the ends of the plurality of outside pipes, and the plurality of inside pipes having a plurality of second connecting members adapted to connect the ends thereof.
The heat pump outdoor unit according to claim 4, further comprising a plurality of fins disposed perpendicular to the lengthwise directions of the first row of outdoor unit coil and the second row of outdoor unit coil so as to expand a heat transfer area.
An alternating type heat pump comprising:

a compressor adapted to compress refrigerant;

a four-way valve adapted to allow the flow direction of high temperature and high pressure refrigerant passed through the compressor to be changed to a heating or cooling circuit;

an indoor unit adapted to perform a heat exchanging operation between indoor air and the refrigerant so as to heat or cool indoor space;

an outdoor unit having a first row of outdoor unit coil and a second row of outdoor unit coil each having an independent refrigerant circuit and disposed in parallel with each other, the first row of outdoor unit coil having a dual pipe structure wherein a plurality of outside pipes and a plurality of inside pipes have an independent refrigerant circuit from each other in such a manner as to be selectively operated as a condenser or evaporator;

heating and cooling expansion valves adapted to reduce temperature and pressure of the flowing refrigerant;

first and second three-way valves each disposed on the refrigerant lines connected to both ends of the outside pipes of the first row of outdoor unit coil so as to change the flow direction of the refrigerant passed through the outside pipes; and

a controller adapted to control the first and second three-way valves such that the outside pipes of the first row of outdoor unit coil are selectively operated as a condenser or evaporator.
The heat pump outdoor unit according to claim 6, further comprising first and second check valves disposed in parallel with the heating and cooling expansion valves and adapted to control the flow direction of the refrigerant in one way, and an accumulator adapted to keep liquid refrigerant from flowing to the compressor.
The alternating type heat pump according to claim 6, wherein upon a standard heating operation, the first and second three-way valves are controlled by means of the controller to allow low temperature and low pressure refrigerant passed through the heating expansion valve to be introduced to the rear ends of the inside pipes and the outside pipes of the first row of outdoor unit coil and to be then introduced to the second row of outdoor unit coil, such that the first row of outdoor unit coil and the second row of outdoor unit coil are all operated as an evaporator.
The alternating type heat pump according to claim 8, wherein upon a defrosting heating operation, the first and second three-way valves are controlled by means of the controller to allow high temperature and high pressure refrigerant emitted from the compressor to be introduced to the outside pipes of the first row of outdoor unit coil, such that the outside pipes of the first row of outdoor unit coil are operated as a condenser.
The alternating type heat pump according to claim 6, wherein upon a standard cooling operation, the first and second three-way valves are controlled by means of the controller to allow high temperature and high pressure refrigerant emitted from the compressor to be introduced to the inside pipes and the outside pipes of the first row of outdoor unit coil and to be then introduced to the second row of outdoor unit coil, such that the first row of outdoor unit coil and the second row of outdoor unit coil are all operated as a condenser.
The alternating type heat pump according to claim 10, wherein upon a cooling operation under the hottest weather conditions, the first and second three-way valves are controlled by means of the controller to allow low temperature and low pressure refrigerant emitted from the cooling expansion valve to be introduced to the outside pipes of the first row of outdoor unit coil, such that the outside pipes of the first row of outdoor unit coil are operated as an evaporator.
An alternating type heat pump comprising:

a compressor adapted to compress refrigerant;

a four-way valve adapted to allow the flow direction of high temperature and high pressure refrigerant passed through the compressor to be changed to a heating or cooling circuit;

an indoor unit adapted to perform a heat exchanging operation between indoor air and the refrigerant so as to heat or cool indoor space;

an outdoor unit having a first row of outdoor unit coil and a second row of outdoor unit coil each having an independent refrigerant circuit and disposed in parallel with each other, the first row of outdoor unit coil and the second row of outdoor unit coil each having a dual pipe structure wherein a plurality of outside pipes and a plurality of inside pipes have an independent refrigerant circuit from each other in such a manner as to be selectively operated as a condenser or evaporator;

heating and cooling expansion valves adapted to reduce temperature and pressure of the flowing refrigerant;

first and second three-way valves disposed between the four-way valve and the front end of the outside pipes of the first row of outdoor unit coil and between the four-way valve and the front end of the outside pipes of the second row of outdoor unit coil so as to change the flow direction of the refrigerant;

a third three-way valve disposed between the outside pipes of the first row of outdoor unit coil and the cooling expansion valve so as to change the flow direction of the refrigerant; and

a controller adapted to control the first to third three-way valves to allow the high temperature and high pressure refrigerant to flow into at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil.
The alternating type heat pump according to claim 12, further comprising a hot gas bypass valve disposed between the first and second three-way valves and the four-way valve so as to control a flow of the high temperature and high pressure refrigerant flowing into at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil.
The alternating type heat pump according to claim 12, further comprising an inside heat exchanger adapted to allow the refrigerant completely not evaporated in the outdoor unit to absorb heat from the refrigerant condensed through the indoor unit and to be completely evaporated, upon a heating operation, thereby increasing the degree of superheat of the refrigerant.
The alternating type heat pump according to claim 12, wherein upon a standard heating operation, the first three-way valve, the second three-way valve, the third three-way valve and the hot gas bypass valve are controlled by means of the controller to allow low temperature and low pressure refrigerant passed through the heating expansion valve to be introduced to the inside pipes and the outside pipes of the first row of outdoor unit coil and to be then introduced to the inside pipes and the outside pipes of the second row of outdoor unit coil, such that the first row of outdoor unit coil and the second row of outdoor unit coil are all operated as an evaporator.
The alternating type heat pump according to claim 15, wherein upon a defrosting heating operation, the first three-way valve, the second three-way valve, the third three-way valve and the hot gas bypass valve are controlled by means of the controller to allow high temperature and high pressure refrigerant emitted from the compressor to be introduced to at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil, such that the at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil are operated as a condenser.
The alternating type heat pump according to claim 12, wherein upon a standard cooling operation, the first three-way valve, the second three-way valve, the third three-way valve and the hot gas bypass valve are controlled by means of the controller to allow high temperature and high pressure refrigerant emitted from the compressor to be introduced to the inside pipes and the outside pipes of the first row of outdoor unit coil and to be then introduced to the inside pipes and the outside pipes of the second row of outdoor unit coil, such that the first row of outdoor unit coil and the second row of outdoor unit coil are all operated as a condenser.
The alternating type heat pump according to claim 17, wherein upon a cooling operation under the hottest weather conditions, the first three-way valve, the second three-way valve, the third three-way valve and the hot gas bypass valve are controlled by means of the controller to allow low temperature and low pressure refrigerant emitted from the cooling expansion valve to be introduced to at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil, such that the at least ones of the outside pipes of the first row of outdoor unit coil and the outside pipes of the second row of outdoor unit coil are operated as an evaporator.